Display device

ABSTRACT

A display is provided. The display device includes a display area and a non-display area located around the display area; a base layer; an organic light-emitting diode (OLED) that is located on the base layer in the display area; and a first crack detection line that is located on the base layer in the non-display area; wherein the first crack detection line comprises a first line that extends substantially in a first direction along a first edge of the display area, a second line that is separated from the first line and extends substantially in the first direction, and a third line that is connected to an end of the first line and an end of the second line, wherein a cross-sectional shape of the first line in a second direction crossing the first direction is inversely tapered.

This application is a continuation application of U.S. patentapplication Ser. No. 15/612,811 filed on Jun. 2, 2017, which claimspriority under 35 USC § 119 to Korean Patent Application No.10-2016-0166618, filed on Dec. 8, 2016, in the Korean IntellectualProperty Office, the disclosures of which are incorporated herein intheir entirety by reference.

BACKGROUND 1. Field

The present inventive concept relates to a display device.

2. Description of the Related Art

Recently, partially bent display devices as well as flat display deviceshave been developed.

In flat display devices or partially bent display devices, cracks mayoccur due to stress, which may cause malfunction of the display devices.Therefore, it is important to accurately detect cracks.

SUMMARY

Aspects of the inventive concept provide a display device whose crackscan be detected easily and more accurately.

However, aspects of the inventive concept are not restricted to the oneset forth herein. The above and other aspects of the inventive conceptwill become more apparent to one of ordinary skill in the art to whichthe inventive concept pertains by referencing the detailed descriptionof the inventive concept given below.

According to an aspect of the inventive concept, there is provided adisplay device. The display device includes a display area and anon-display area located around the display area; a base layer; anorganic light-emitting diode (OLED) that is located on the base layer inthe display area; and a first crack detection line that is located onthe base layer in the non-display area; wherein the first crackdetection line comprises a first line that extends substantially in afirst direction along a first edge of the display area, a second linethat is separated from the first line and extends substantially in thefirst direction, and a third line that is connected to an end of thefirst line and an end of the second line, wherein a cross-sectionalshape of the first line in a second direction crossing the firstdirection is inversely tapered.

According to another aspect of the inventive concept, there is provideda display device. The display device includes a display area and anon-display area located around the display area; a base layer; athin-film transistor that is located on the base layer in the displayarea; a pad that is located on the base layer in the non-display area; adata line that is located on the base layer, extends substantially in afirst direction, is electrically connected to the thin-film transistorin the display area, and is electrically connected to the pad in thenon-display area; and a crack detection pattern that is located betweenan edge of the base layer and the data line in the non-display area andseparated from the data line, wherein a cross-sectional shape of thecrack detection line in a second direction crossing the first directionis inversely tapered.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a schematic plan view of a display device according to anembodiment;

FIG. 2 is an equivalent circuit diagram of one pixel element of thedisplay device according to the embodiment of FIG. 1;

FIG. 3 is an enlarged plan view of a portion of ‘S’ of FIG. 1;

FIG. 4 is a cross-sectional view taken along the line A-A′ of FIG. 3;

FIG. 5 is a cross-sectional view taken along the lines B-B′ and C-C′ ofFIG. 1;

FIGS. 6, 7, 8, 9 10, 11, 12 and 13 are cross-sectional viewsillustrating the process of manufacturing the portion of FIG. 4;

FIGS. 14, 15, 16, 17 and 18 are cross-sectional views illustrating theprocess of manufacturing the portion of FIG. 5;

FIG. 19 is a schematic perspective view of the structure of the displaydevice of FIG. 1 in a case where the display device is bent;

FIG. 20 is a cross-sectional view taken along the line X-X′ of FIG. 19;

FIG. 21 is a cross-sectional view taken along the line Y-Y′ of FIG. 19;

FIG. 22 is a schematic perspective view of the structure of a modifiedembodiment of the display device illustrated in FIG. 19;

FIG. 23 is a cross-sectional view taken along the line Xa-Xa′ of FIG.22;

FIG. 24 is a cross-sectional view taken along the line Ya-Ya′ of FIG.22;

FIG. 25 is a schematic perspective view of the structure of a modifiedembodiment of the display device illustrated in FIG. 19;

FIG. 26 is a cross-sectional view taken along the line Xb-Xb′ of FIG.25;

FIG. 27 is a cross-sectional view taken along the line Yb-Yb′ of FIG.25; and

FIG. 28 is a cross-sectional view of modified examples of across-sectional shape of a first line of a first crack detection lineillustrated in FIG. 4.

DETAILED DESCRIPTION

Features of the inventive concept and methods of accomplishing the samemay be understood more readily by reference to the following detaileddescription of embodiments and the accompanying drawings. The inventiveconcept may, however, be embodied in many different forms and should notbe construed as being limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete and will fully convey the concept of the inventiveconcept to those skilled in the art, and the inventive concept will onlybe defined by the appended claims. Like reference numerals refer to likeelements throughout the specification.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the inventiveconcept. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” or “coupled to” another element or layer, itmay be directly on, connected or coupled to the other element or layer,or intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on”, “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, although the terms first, second, etc., maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections are not limited by these terms. These terms are only used todistinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings of the inventive concept.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper”, and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations), and the spatiallyrelative descriptors used herein are to be interpreted accordingly.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which the present application belongs.It will be further understood that terms, such as those defined incommonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand this specification and not be interpreted in an idealized or overlyformal sense unless expressly so defined herein.

In the following embodiments, the x-axis, the y-axis, and the z-axis arenot limited to three axes on an orthogonal coordinate system but may beinterpreted in a broad sense, including the three axes. For example, thex-, y-, and z-axes may be orthogonal to each other but may also refer todifferent directions that are not orthogonal to each other.

Throughout the specification, same or like reference characters in thedrawings denote same or like elements.

Hereinafter, embodiments of the inventive concept will be described withreference to the attached drawings.

FIG. 1 is a schematic plan view of a display device 1 according to anembodiment. FIG. 2 is an equivalent circuit diagram of one pixel elementPX of the display device 1 according to the embodiment of FIG. 1. FIG. 3is an enlarged plan view of a portion ‘S’ of FIG. 1.

Referring to FIG. 1, the display device 1 according to the embodimentincludes a display area DA in which an image recognizable by a user isdisplayed and a non-display area NDA which is located around the displayarea DA. The non-display area NDA includes a pad area PA. The displayarea DA is an area in which pixel elements PX are disposed to form animage, and the non-display area NDA is an area in which no image isformed. The pad area PA of the non-display area NDA is an area in whichpads for transmitting external power and control signals to each elementof the display device 1 are located.

If a vertical direction y is referred to as a first direction and ahorizontal direction x as a second direction on the basis of thedrawing, the display area DA may include a first edge e1 that is locatedon a left side of the drawing, a second edge e2 that faces the firstedge e1 and is located on a right side of the drawing, a third edge e3that is located between the first edge e1 and the second edge e2 andpositioned on an upper side of the drawing, and a fourth edge e4 thatfaces the third edge e3 and is located on a lower side of the drawing.The pad area PA may be located outside the fourth edge e4 of the displayarea DA.

A plurality of signal lines (121 and 171) and a pixel element PX arelocated on a base layer 110 of the display device 1.

The pixel element PX is located in the display area DA and may beprovided in a plurality in the display area DA. The pixel element PXdenotes a group of elements included in one pixel, which is a minimumunit for displaying an image.

The signal lines (121 and 171) include a gate line 121, which delivers agate signal or a scan signal and extends in the second direction x, anda data line 171, which delivers a data signal, extends in the firstdirection y that crosses the second direction x, and is insulated fromthe gate line 121. The gate line 121 and the data line 171 may belocated in the display area DA, and part of the gate line 121 and partof the data line 171 may extend up to the non-display area NDA.

A data pad P1 may be located on the base layer 110 and in the pad areaPA. The data pad P1 delivers a data voltage received from an externalsource to the data line 171. The data pad P1 may be connected to thedata line 171 extending to the non-display area NDA, more specifically,to the pad area PA.

Although not illustrated in FIG. 1, a driving voltage line 172 (see FIG.2) for delivering a driving voltage may further be disposed on the baselayer 110 of the display device 1. The driving voltage line 172 mayextend substantially parallel to the data line 171.

Referring to FIG. 2, each pixel element PX includes a driving thin-filmtransistor Qd as a switching element, a switching thin-film transistorQs as a switching element, a storage capacitor Cst and an organiclight-emitting diode (OLED) LD, and further includes part of the gateline 121, part of the data line 171 and part of the driving voltage line172.

The driving thin-film transistor Qd has a control terminal, an inputterminal and an output terminal. The control terminal is connected tothe switching thin-film transistor Qs, the input terminal is connectedto the driving voltage line 172, which provides a driving voltage Vdd,and the output terminal is connected to the OLED LD. The drivingthin-film transistor Qd controls an electric current I supplied to theOLED LD.

The switching thin-film transistor Qs also has a control terminal, aninput terminal and an output terminal. The control terminal is connectedto the gate line 121, the input terminal is connected to the data line171, and the output terminal is connected to the control terminal of thedriving thin-film transistor Qd. The switching thin-film transistor Qsdelivers a data voltage applied to the data line 171 to the drivingthin-film transistor Qd in response to a scan signal transmitted to thegate line 121.

The storage capacitor Cst is connected between the control terminal andthe input terminal of the driving thin-film transistor Qd. The storagecapacitor Cst is charged with a data voltage applied to the controlterminal of the driving thin-film transistor Qd and maintains thecharged data voltage for a predetermined period even after the switchingthin-film transistor Qs is turned off.

The OLED LD includes an anode, which is connected to the output terminalof the driving thin-film transistor Qd, a cathode, which is connected toa common voltage line providing a common voltage Vss, and an organiclight-emitting layer. The OLED LD emits light with different intensityaccording to the electric current I output from the driving thin-filmtransistor Qd so as to display an image.

In the embodiment described above, in relation to each of the switchingthin-film transistor Qs and the driving thin-film transistor Qd, thecontrol terminal may be a gate electrode, the input terminal may be anyone of a source electrode and a drain electrode, and the output terminalmay be the other one of the source electrode and the drain electrode.For example, when the input terminal is a source electrode, the outputterminal may be a drain electrode.

Referring back to FIG. 1, a first crack detection line CD1 may belocated on the base layer 110 of the display device 1. The first crackdetection line CD1 may be located in the non-display area NDA.

The first crack detection line CD1 may be located in the non-displayarea NDA outside the first edge e1 of the display area DA.

The first crack detection line CD1 may include a first line CD1 a thatextends substantially in the first direction y along the first edge e1of the display area DA, a second line CD1 b that is separated from thefirst line CD1 a and extends substantially in the first direction y, anda third line CD1 c that connects an end of the first line CD1 a and anend of the second line CD1 b.

The first line CD1 a and the second line CD1 b may be located in thenon-display area NDA outside a left side of the display area DA. In someembodiments, the third line CD1 c may be located outside an upper sideof the display area DA or located in the non-display area NDA outsidethe third edge e3 of the display area DA as illustrated in FIG. 1.

A cross-sectional shape of the first line CD1 a in the second directionx may be inversely tapered. In some embodiments, a cross-sectional shapeof the second line CD1 b in the second direction x may also be inverselytapered. Also, in some embodiments, a cross-sectional shape of the thirdline CD1 c in the first direction y may be inversely tapered. When acrack is generated in the non-display area NDA of the display device 1,it may be transmitted to the first crack detection line CD1, thuspartially damaging or breaking the first crack detection line CD1. Inparticular, when the cross-sectional shape of at least any one of thefirst line CD1 a and the second line CD1 b is inversely tapered, forexample, has a smaller lower width than an upper width, the first crackdetection line CD1 can be more easily damaged or broken by the crack.Therefore, cracks in the display device 1 can be easily detected,thereby preventing defects of the display device 1 due to cracks.

Referring to FIG. 3, the first crack detection line CD1 may be spacedapart from an edge E of the base layer 110 by a predetermined distance.This is to prevent the first crack detection line CD1 from being damagedin the process of cutting a mother substrate during the process ofmanufacturing a display device. In some embodiments, a shortest gap ordistance L1 between the first crack detection line CD1 and the edge E ofthe base layer 110 may be 50 to 100 μm.

In some embodiments, a line width W of the first line CD1 a, i.e., awidth of the first line CD1 a measured along the second direction x, maybe in a range of 5 to 10 μm. Similarly, a line width of the second lineCD1 b may also be in a range of 5 to 10 μm.

In some embodiments, a distance L2 between the first line CD1 a and thesecond line CD1 b measured along the second direction x may be in arange of 15 to 20 μm.

Referring back to FIG. 1, like the first crack detection line CD1, asecond crack detection line CD2 may be located on the base layer 110 ofthe display device 1. The second crack detection line CD2 may be locatedin the non-display area NDA of the display device 1. The second crackdetection line CD2 may be located in the non-display area NDA outsidethe second edge e2 of the display area DA.

The second crack detection line CD2 may include a fourth line CD2 a thatextends substantially in the first direction y along the second edge e2of the display area DA, a fifth line CD2 b that is separated from thefourth line CD2 a and extends substantially in the first direction y,and a sixth line CD2 c that connects an end of the fourth line CD2 a andan end of the fifth line CD2 b. A cross-sectional shape of the fourthline CD2 a in the second direction x may be inversely tapered. In someembodiments, a cross-sectional shape of the fifth line CD2 b in thesecond direction x may also be inversely tapered. Also, in someembodiments, a cross-sectional shape of the sixth line CD2 c in thefirst direction y may be inversely tapered.

That is, the first and second crack detection lines CD1 and CD2 areformed in the non-display area NDA adjacent to both edges of the displayarea DA and are formed in the shape of a hemiring.

However, the shape of each of the first and second crack sensing linesCD1 and CD2 is not limited to the shape in the above embodiment. Forexample, the first crack detection line CD1 may further include a lineextending along the first direction y in addition to the first line CD1a and the second line CD1 b. In this case, a connector that connects thesecond line CD1 b and the additional line may be further included in thefirst crack detection line CD1. Similarly, the second crack detectionline CD2 may further include an additional line and a connector inaddition to the fourth line CD2 a and the fifth line CD2 b.

First through fourth test pads TP1 through TP4 may be positioned in thepad area PA. The first test pad TP1 and the second test pad P2 transmittest signals for detecting cracks to the first crack detection line CD1.An end of the first line CD1 a may extend up to the pad area PA to beconnected to the first test pad TP1, and an end of the second line CD1 bmay extend up to the pad region PA to be connected to the second testpad TP2.

There is a high probability that no crack will occur in the displaydevice 1 before the process of cutting a mother substrate or before theprocess of bending part of the display device 1. When a crack isgenerated in the display device 1 and damage is done to the first crackdetection line CD1, a resistance value of the first crack detection lineCD1 may increase, and the first crack detection line CD1 may bepartially broken.

Therefore, a voltage is applied to the first test pad TP1 and the secondtest pad TP2 before the cutting process or the bending process to obtaina first test value (e.g., an electric current value), the voltage isapplied to the first test pad TP1 and the second test pad TP2 after thecutting process or the bending process to obtain a second test value(e.g., an electric current value), and the first test value and thesecond test value are compared to determine whether a crack has occurredin the display device 1.

However, the above-described crack detection process is merely anexample, and whether a crack has occurred in the display device 1 can bedetected in various ways using the first crack detection line CD1.

Like the first test pad TP1 and the second test pad TP2, the third testpad TP3 and the fourth test pad TP4 transmit test signals for detectingcracks to the second crack detection line CD2. An end of the fourth lineCD2 a may extend up to the pad area PA to be connected to the third testpad TP3, and an end of the fifth line CD2 b may extend up to the padregion PA to be connected to the fourth test pad TP4.

A first crack detection pattern CDP1 for detecting cracks in the padarea PA may be located in the pad area PA. The first crack detectionpattern CDP1 may be separated from the data line 171 located in the padarea PA and may be disposed between a left edge of the base layer 110and a leftmost data line 171.

In some embodiments, the first crack detection pattern CDP1 may includea first pattern CDP1 a that extends in the first direction y, a secondpattern CDP1 b that is separated from the first pattern CDP1 a andextends in the first direction y, and a first connection pattern CDP1 cthat connects the first pattern CDP1 a and the second pattern CDP1 b.

In some embodiments, a cross-sectional shape of the first pattern CDP1 ain the second direction x may be inversely tapered, and across-sectional shape of the second pattern CDP1 b in the seconddirection x may also be inversely tapered. Accordingly, cracks occurringin the pad area PA of the display device 1 can be easily detected.

A second crack detection pattern CDP2 may further be provided on theopposite side of the pad area PA to the first crack detection patternCDP1. The second crack detection pattern CDP2 may be separated from thedata line 171 located in the pad area PA and may be disposed between aright edge of the base layer 110 and a rightmost data line 171.

In some embodiments, like the first crack detection pattern CDP1, thesecond crack detection pattern CDP2 may include a third pattern CDP2 athat extends in the first direction y, a fourth pattern CDP2 b that isseparated from the third pattern CDP2 a and extends in the firstdirection y, and a second connection pattern CDP2 c that connects thethird pattern CDP2 a and the fourth pattern CDP2 b. In some embodiments,a cross-sectional shape of the third pattern CDP2 a in the seconddirection x may be inversely tapered, and a cross-sectional shape of thefourth pattern CDP2 b in the second direction x may also be inverselytapered.

A fifth test pad TP11, a sixth test pad TP12, a seventh test pad TP21and an eighth test pad TP22 to which test signals for detecting cracksare transmitted are located on the base layer 110 in the pad area PA.The fifth test pad TP11 may be connected to the first pattern CDP1 a,the sixth test pad TP12 may be connected to the second pattern CDP1 b,the seventh test pad TP21 may be connected to the third pattern CDP2 a,and the eighth test pad TP22 may be connected to the fourth pattern CDP2b. The crack detection process is the same as or similar to thatdescribed above in the description of the first crack detection lineCD1, and thus a description of the crack detection process is omitted.

A dam DM may be located on the base layer 110 in the non-display areaNDA in order to prevent organic matter located in the display area DAfrom flowing over the edge of the base layer 110. In FIG. 1, one dam DMis illustrated as an example. However, in some other embodiments, two ormore dams DM may be formed.

The dam DM may surround the display area DA and may be located betweenthe first and second crack detection lines CD1 and CD2 and the displayarea DA. In other words, the first crack detection line CD1 and thesecond crack detection line CD2 may be located relatively further fromthe center than the dam DM.

The layer structure of the display device 1 according to the embodimentwill hereinafter be described in detail with reference to the drawings.Since the switching thin-film transistor Qs and the driving thin-filmtransistor Qd of each pixel element PX have the same layer structure,the layer structure of the display device 1 will be described in detailaccording to a stacking sequence, focusing mainly on the drivingthin-film transistor Qd and the OLED LD of the pixel element PX. Adriver circuit for driving the pixel element PX may also be formed inthe non-display area NDA of the display device 1. Since the drivercircuit includes a plurality of signal lines and a plurality ofthin-film transistors, one circuit thin-film transistor Ts will bedescribed as an example. In the following description, elements andfeatures identical to those described above will be mentioned briefly oromitted.

FIG. 4 is a cross-sectional view taken along the line A-A′ of FIG. 3.FIG. 5 is a cross-sectional view taken along the lines B-B′ and C-C′ ofFIG. 1.

Referring to FIGS. 1 and 3 through 5, the base layer 110 of the displaydevice 1 may be made of transparent resin. For example, the base layer110 may include polymethylmethacrylate resin, polyimide resin, acrylicresin, polyacrylate resin, polycarbonate resin, polyether resin,sulfonic acid resin, polyethylene terephthalate resin, etc. The baselayer 110 may be a transparent flexible substrate having flexibilitysuch as elasticity. That is, the base layer 110 is foldable, bendable,rollable, or stretchable in at least one direction. In an embodiment,the base layer 110 may be a transparent ceramic substrate such as aglass substrate, a quartz substrate or a transparent alumina substrate.

A buffer layer 111 may be located on the base layer 110. The bufferlayer 111 may be made of a silicon compound, transparent resin, or thelike. For example, the buffer layer 111 may include at least one bufferfilm that contains silicon oxide, silicon nitride, silicon oxycarbide,silicon carbonitride, polyacrylate resin, polymethacrylate resin, olefinresin and/or polyvinyl resin. According to embodiments, the buffer layer111 may include two buffer films made of different silicon compounds.Alternatively, the buffer layer 111 may have a structure in which atleast one buffer film containing a silicon compound and at least onebuffer film containing transparent resin are stacked substantiallyalternately. However, the structure of the buffer layer 111 may varydepending on the configuration, dimensions, use, etc., of the displaydevice 1. The buffer layer 120 may prevent penetration of unnecessarycomponents such as impurities, metal atoms and moisture. In addition,the buffer layer 111 may planarize the surface of the base layer 110.

A semiconductor layer 135 of the driving thin-film transistor Qd andsemiconductor layer 35 of the circuit thin-film transistor Ts may belocated on the buffer layer 111. Each of the semiconductor layers 35 and135 may be made of polysilicon, an oxide semiconductor, or the like. Theoxide semiconductor may include at least one of an oxide of titanium(Ti), hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta),germanium (Ge), zinc (Zn), gallium (Ga), tin (Sn) or indium (In) andcomposite oxides of these materials such as indium-gallium-zinc oxide(InGaZnO4), indium-zinc oxide (In—Zn—O), zinc-tin oxide (Zn—Sn—O)indium-gallium oxide (In—Ga—O), indium-tin oxide (In—Sn—O),indium-zirconium oxide (In—Zr—O), indium-zirconium-zinc oxide(In—Zr—Zn—O), indium-zirconium-tin oxide (In—Zr—Sn—O),indium-zirconium-gallium oxide (In—Zr—Ga—O), indium-aluminum oxide(In—Al—O), indium-zinc-aluminum oxide (In—Zn—Al—O), indium-tin-aluminumoxide (In—Sn—Al—O), indium-aluminum-gallium oxide (In—Al—Ga—O),indium-tantalum oxide (In—Ta—O), indium-tantalum-zinc oxide(In—Ta—Zn—O), indium-tantalum-tin oxide (In—Ta—Sn—O),indium-tantalum-gallium oxide (In—Ta—Ga—O), indium-germanium oxide(In—Ge—O), indium-germanium-zinc oxide (In—Ge—Zn—O),indium-germanium-tin oxide (In—Ge—Sn—O), indium-germanium-gallium oxide(In—Ge—Ga—O), titanium-indium-zinc oxide (Ti—In—Zn—O) andhafnium-indium-zinc oxide (Hf—In—Zn—O). When the semiconductor layers 35and 135 are made of an oxide semiconductor, a protective layer may beadded to protect the oxide semiconductor, which is vulnerable toexternal environments such as high temperatures.

A gate insulating layer 113, which covers the semiconductor layers 35and 135, may be disposed on the buffer layer 111. The gate insulatinglayer 113 may be made of a silicon compound such as silicon oxide orsilicon carbide. Alternatively, the gate insulating layer 113 may bemade of a metal oxide such as hafnium oxide, aluminum oxide, zirconiumoxide, titanium oxide or tantalum oxide.

Gate electrodes 25 and 125 may be located on the gate insulating layer113 and may overlap the semiconductor layers 35 and 135. Each of thegate electrodes 25 and 125 may be a single layer or a multilayer made ofa low-resistance material or a highly corrosive material such as Al, Ti,Mo, Cu, Ni, or an alloy of these materials.

A first interlayer insulating film 115, which covers the gate electrodes25 and 125, may be disposed on the gate insulating layer 113. The firstinterlayer insulating film 115 may separate the gate electrode 25 of thecircuit thin-film transistor Ts and the gate electrode 125 of thedriving thin-film transistor Qd from wiring layers and/or electrodesdisposed on the gate electrodes 25 and 125. The first interlayerinsulating film 115 may include a silicon compound, transparent resin,or the like. For example, the first interlayer insulating film 115 mayinclude silicon oxide, silicon nitride, silicon oxynitride, siliconcarbonitride, silicon oxycarbide, polyacrylate resin, polymethacrylateresin, olefin resin, polyvinyl resin, or the like.

A power supply line 71, the data line 171, source electrodes 73 and 173,and drain electrodes 75 and 175 may be located on the first interlayerinsulating film 115. In some embodiments, the power supply line 71 maybe the common voltage line to which the common voltage Vss (see FIG. 2)described above with reference to FIG. 2 is applied.

The source electrode 73 and the drain electrode 75 of the circuitthin-film transistor Ts may be electrically connected to thesemiconductor layer 35 of the circuit thin-film transistor Ts throughcontact holes formed in the first interlayer insulating film 115 and thegate insulating layer 113.

The source electrode 173 and the drain electrode 175 of the drivingthin-film transistor Qd may be connected to the semiconductor layer 135of the driving thin-film transistor Qd through contact holes formed inthe first interlayer insulating film 115 and the gate insulating layer113.

Each of the power supply line 71, the data line 171, the sourceelectrodes 73 and 173 and the drain electrodes 75 and 175 may be asingle layer or a multilayer made of a low-resistance material or ahighly corrosive material such as Al, Ti, Mo, Cu, Ni, or an alloy ofthese materials. For example, the multilayer may be a triple layer ofTi/Cu/Ti, Ti/Ag/Ti, or Mo/Al/Mo.

The semiconductor layer 135, the gate electrode 125, the sourceelectrode 173 and the drain electrode 175 located in the display area DAform the driving thin-film transistor Qd serving as a switching element.Similarly, the semiconductor layer 35, the gate electrode 25, the sourceelectrode 73 and the drain electrode 75 located in the non-display areaNDA form the circuit thin-film transistor Ts serving as a switchingelement.

A second interlayer insulating film 117, which covers the drivingthin-film transistor Qd and the data line 171 of the display area DA,may be located on the first interlayer insulating film 115. The secondinterlayer insulating film 117 may cover the circuit thin-filmtransistor Ts and extend up to the non-display area NDA to partiallycover the power supply line 71.

The second interlayer insulating film 117 may be made of an organicmaterial. For example, the second interlayer insulating film 117 mayinclude polyimide resin, photoresist, acrylic resin, polyamide resin,siloxane resin, or the like. These materials may be used alone or incombination with each other. In other embodiments, the second interlayerinsulating film 117 may be made of an inorganic material such as asilicon compound, a metal oxide, or the like. For example, the secondinterlayer insulating film 117 may include silicon oxide, siliconnitride, silicon oxynitride, silicon oxycarbide, silicon carbonitride,aluminum oxide, titanium oxide, tantalum oxide, magnesium oxide, zincoxide, hafnium oxide, zirconium oxide, titanium oxide, or the like.

A connection electrode 211 and a first electrode 210 may be located onthe second interlayer insulating film 117. The first electrode 210 maybe electrically connected to the drain electrode 175 of the drivingthin-film transistor Qd through a contact hole formed in the secondinterlayer insulating film 117. The first electrode 210 may be the anodeof the OLED LD.

The connection electrode 211 and the first electrode 210 may be made ofthe same material. In an example, each of the connection electrode 211and the first electrode 210 may include a reflective film made of Ag,Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a compound of these materials anda transparent or translucent electrode layer formed on the reflectivefilm. The transparent or translucent electrode layer may include atleast one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), indium oxide (In₂O₃), indium gallium oxide (IGO), and aluminumzinc oxide (AZO).

The connection electrode 211 may be connected to the power supply line71 and may contact the power supply line 71.

A pixel defining layer 220 may be disposed on the second interlayerinsulating film 117 in the display area DA. The pixel defining layer 220may include an opening that exposes the first electrode 210. In someembodiments, the pixel defining layer 220 may extend on part of thesecond interlayer insulating film 117 to overlap the data line 171located in the display area DA. The pixel defining layer 220 may includean organic material. For example, the pixel defining layer 220 maycontain polyimide resin, photoresist, polyacrylic resin, polyamideresin, acrylic resin, or the like.

A light emitting layer 230 may be disposed on the first electrode 210,which is exposed by the opening of the pixel defining layer 220. Thelight emitting layer 230 may have a multilayer structure including anorganic light emitting layer (EL), a hole injection layer (HIL), a holetransport layer (HTL), an electron transport layer (ETL), and anelectron injection layer (EIL). In some embodiments, the organic lightemitting layer of the light emitting layer 230 may include a lightemitting material capable of generating light of different colors, suchas red light, green light, and blue light, according to the pixel typeof the display device 1. In other embodiments, the organic lightemitting layer of the light emitting layer 230 may include a stack of aplurality of light emitting materials capable of generating light ofdifferent colors such as red light, green light and blue light.Consequently, white light may be emitted from the organic light emittinglayer of the light emitting layer 230.

A second electrode 250 may be disposed on the light emitting layer 230and the pixel defining layer 220. The second electrode 250 may be thecathode. The second electrode 250 may extend to the non-display area NDAand may contact the connection electrode 211. Accordingly, the commonvoltage Vss (see FIG. 2) provided to the power supply line 71 may beprovided to the second electrode 250 through the connection electrode211. The second electrode 250 may be made of a metal, an alloy, a metalnitride, a conductive metal oxide, a transparent conductive material, orthe like.

The first electrode 210, the light emitting layer 230 and the secondelectrode 250 form the OLED LD. The OLED LD and the pixel defining layer220 may form a display structure DS.

As described above with reference to FIG. 1, the dam DM may be locatedin the non-display area NDA of the display device 1. The dam DM mayprevent an organic film 330 of a thin-film encapsulation layer 300,which will be described later, from spreading non-ideally to the edge ofthe display device 1.

The dam DM may be located relatively further from the center than thepower line 71. In other words, a distance between the dam DM and thedisplay area DA may be greater than a distance between the power supplyline 71 and the display area DA. That is, the power supply line 71 maybe positioned between the dam DM and the display area DA.

In some embodiments, the dam DM may include a first pattern 117 a thatis located on the first interlayer insulating film 115 and a secondpattern 220 a that is located on the first pattern 117 a. In an example,the first pattern 117 a may be made of the same material as the secondinterlayer insulating film 117, and the second pattern 220 a may be madeof the same material as the pixel defining layer 220.

In some embodiments, the dam DM may partially overlap the power supplyline 71 and may be separated from the second interlayer insulating film117 with the power supply line 71 interposed between them. The dam DMmade of the same material as at least any one of the second interlayerinsulating film 117 and the pixel defining layer 220 may have goodbonding strength with metal. Therefore, if the dam DM is formed tocontact the power supply line 71 made of a metal material, the dam DMcan be stably formed to have excellent bonding strength.

The first crack detection line CD1 may be located in the non-displayarea NDA of the display device 1. The first crack detection line CD1 mayinclude the first line CD1 a and the second line CD1 b. The first crackdetection line CD1 may be located relatively further from the centerthan the dam DM and the power supply line 71. In other words, a distancebetween the first crack detection line CD1 and the display area DA maybe greater than the distance between the dam DM and the display area DAand the distance between the power supply line 71 and the display areaDA. That is, the dam DM and the power supply line 71 may be locatedbetween the first crack detection line CD1 and the display area DA.

The first crack detection line CD1 may be formed on the same layer andof the same material as the power supply line 71, the data line 171, thesource electrodes 73 and 173 and the drain electrodes 75 and 175.

The thin-film encapsulation layer 300 for sealing the display structureDS may be disposed on the display structure DS of the display area DA.The thin-film encapsulation layer 300 may also be disposed in part ofthe non-display area NDA.

The thin-film encapsulation layer 300 may include one or more organicfilms and one or more inorganic films. In some embodiments, thethin-film encapsulation layer 300 may include at least one sandwichstructure in which at least one organic film is interposed between atleast two inorganic films. The thin-film encapsulation layer 300including a first inorganic film 310, a second inorganic film 350 andthe organic film 330 disposed between the first inorganic film 310 andthe second inorganic film 350 will hereinafter be described as anexample of the thin-film encapsulation layer 300.

The first inorganic film 310 may be positioned on the second electrode250 in the display area DA. In the non-display area NDA, the firstinorganic film 310 may cover the connection electrode 211 and the damDM. In some embodiments, the first inorganic film 310 may contact thefirst interlayer insulating film 115 on the outside of the dam DM. Thefirst inorganic film 310 may prevent the display structure DS fromdeteriorating due to penetration of moisture, oxygen, and the like. Thefirst inorganic film 310 may be made of silicon nitride, aluminumnitride, zirconium nitride, titanium nitride, hafnium nitride, tantalumnitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide,cerium oxide, silicon oxynitride (SiON), or the like.

The organic film 330 may be located on the first inorganic film 310. Theorganic film 330 may improve the flatness of the display device 1 andprotect the display structure DS in the display area DA. The organicfilm 330 may be made of a liquid organic material such as acrylic resin,methacrylic resin, polyisoprene, vinyl resin, epoxy resin, urethaneresin, cellulose resin or perylene resin. This organic material may beprovided on the base layer 110 through deposition, printing or coatingand may be subjected to a curing process. When the organic material in aliquid state is cured in a state in which it is spread wider than aninorganic film, shrinkage occurs due to moisture permeation. In thecurrent embodiment, the dam DM for preventing the spread of the liquidorganic material is provided to control the non-ideal spread of theorganic material.

As described above, the spread of the organic film 330 can be controlledby the dam DM. Accordingly, the area of the organic film 330 may besmaller than the area of the first inorganic film 310. In someembodiments, the organic film 330 may be located inside the dam DM. Inother words, in some embodiments, the organic film 330 may be locatedonly in the display area DA and in a region of the non-display area NDAbetween the display area DA and the dam DM.

The second inorganic film 350 may be located on the organic film 330.The second inorganic film 350 may have substantially the same or similarrole as the first inorganic film 310 and may be made of substantiallythe same or similar material as the first inorganic film 310. The secondinorganic film 350 may completely cover the organic film 330. The secondinorganic film 350 may be located on the first inorganic film 310, whichcovers the dam DM and contacts the first interlayer insulating film 115on the outside of the dam DM. Accordingly, the first inorganic film 310and the second inorganic film 350 may contact each other on an upperside of the dam DM or on the outside of the dam DM.

A first inorganic film pattern PT1 including a first lower inorganicfilm pattern 310 a and a first upper inorganic film pattern 350 a may belocated on the first line CD1 a. In addition, a second inorganic filmpattern PT2 including a second lower inorganic film pattern 310 b and asecond upper inorganic film pattern 350 b may be located on the secondline CD1 b. A third inorganic film pattern PT3 disposed on the firstinterlayer insulating film 115 may be located between the first line CD1a and the second line CD2 a. The third inorganic film pattern PT3 mayinclude a third lower inorganic film pattern 310 c and a third upperinorganic film pattern 350 c. The first inorganic film pattern PT1 andthe second inorganic film pattern PT2 may be separated from the firstinorganic film 310 and the second inorganic film 350 of the thin-filmencapsulation layer 300. In addition, the first inorganic film patternPT1 and the second inorganic film pattern PT2 may be separated from thethird inorganic film pattern PT3.

The first lower inorganic film pattern 310 a, the second lower inorganicfilm pattern 310 b and the third lower inorganic film pattern 310 c maybe made of the same material as the first inorganic film 310 of thethin-film encapsulation layer 300. The first upper inorganic filmpattern 350 a, the second upper inorganic film pattern 350 b and thethird upper inorganic film pattern 350 c may be made of the samematerial as the second inorganic film 350 of the thin-film encapsulationlayer 300.

A first inorganic material may be deposited on the first line CD1 a andthe second line CD1 b when it is deposited to form the first inorganicfilm 310 of the thin-film encapsulation layer 300. The first inorganicmaterial may also be deposited in a space between the first line CD1 aand the second line CD1 b. Likewise, a second inorganic material may bedeposited on the first line CD1 a and the second line CD1 b when it isdeposited to form the second inorganic film 350 of the thin-filmencapsulation layer 300. The second inorganic material may also bedeposited in a space between the first line CD1 a and the second lineCD1 b.

As described above, the cross-sectional shape of the first line CD1 a inthe second direction x may have the smaller lower width than the upperwidth, that is, may be inversely tapered. In some embodiments, thecross-sectional shape of the second line CD1 b in the second direction xmay also be inverted tapered. Therefore, the first lower inorganic filmpattern 310 a and the second lower inorganic film pattern 310 b formedby depositing the first inorganic material on the first line CD1 a andthe second line CD1 b may be separated from the third lower inorganicfilm pattern 310 c and the first inorganic film 310. Similarly, thefirst upper inorganic film pattern 350 a and the second upper inorganicfilm pattern 350 b formed on the first lower inorganic film pattern 310a and the second lower inorganic film pattern 310 b may be separatedfrom the third upper inorganic film pattern 350 c and the secondinorganic film 350.

When the cross-sectional shape of each of the first line CD1 a and thesecond line CD1 b is tapered, for example, has a wider lower surfacethan an upper surface, even if a crack occurs in the non-display areaNDA, there is a high probability that the crack will not be transmittedto the first crack detection line CD1. For example, the first crackdetection line CD1 is highly likely to be not damaged or damaged onlyslightly, and it is difficult for the first crack detection line CD1 tobe broken.

On the other hand, according to the current embodiment, thecross-sectional shape of each of the first line CD1 a and the secondline CD1 b is inversely tapered. Therefore, the first crack detectionline CD1 can be more easily damaged or broken by a crack generated inthe non-display area NDA. Accordingly, cracks in the display device 1can be easily detected, thereby preventing defects of the display device1 due to cracks.

In FIG. 4, the cross-sectional shape of each of the first line CD1 a andthe second line CD1 b has a flat inclined surface and is monotonouslyreduced in width toward the base layer 110 or the first interlayerinsulating film 115, but the inventive concept is not limited to thisexample.

FIG. 28 is a cross-sectional view of modified examples of thecross-sectional shape of the first line CD1 a of the first crackdetection line CD1 in the display device 1 according to the embodiment.As illustrated in (a) through (n) of FIG. 28, the cross-sectional shapeof the first line CD1 a may have a curved inclined surface or may bereduced in width in stages. Like the cross-sectional shape of the firstline CD1 a, the cross-sectional shape of the second line CD1 b may alsobe variously modified.

Referring back to FIGS. 1 and 3 through 5, in some embodiments, like thecross-sectional shape of the first crack detection line CD1, across-sectional shape of each of the first test pad TP1 and the secondtest pad TP2 located in the pad area PA of the non-display area NDA maybe inversely tapered. The first test pad TP1 and the second test pad TP2may be formed by the same process as that for the first crack detectionline CD1. Therefore, when the first crack detection line CD1 is formedto have an inversely tapered cross-sectional shape, each of the firsttest pad TP1 and the second test pad TP2 may also be formed to have aninversely tapered cross-sectional shape.

Although not illustrated in the drawings, like the cross-sectional shapeof the first crack detection line CD1, a cross-sectional shape of atleast any one of the fourth line CD2 a and the fifth line CD2 b of thesecond crack detection line CD2 in the second direction x may beinversely tapered. In some embodiments, a cross-sectional shape of eachof the third test pad TP3 and the fourth test pad TP4 may also beinversely tapered.

In addition, the cross-sectional shape of at least any one of the firstpattern CDP1 a and the second pattern CDP1 b of the first crackdetection pattern CDP1 in the second direction x may be inverselytapered as described above. Thus, cracks occurring in the pad area PAcan be more easily detected.

Although not illustrated in the drawings, like the cross-sectional shapeof the first crack detection pattern CDP1, the cross-sectional shape ofat least any one of the third pattern CDP2 a and the fourth pattern CDP2b of the second crack detection pattern CDP2 in the second direction xmay be inversely tapered.

In some embodiments, the thin-film encapsulation layer 300 may not bedisposed in the pad area PA of the non-display area NDA. Accordingly,the thin-film encapsulation layer 300 may not be located on the firsttest pad TP1 and the second test pad TP2 located in the pad area PA.Therefore, the first test pad TP1 and the second test pad TP2 may notcontact nor overlap the thin-film encapsulation layer 300. Likewise, thefirst and second crack detection patterns CDP1 and CDP2 may not contactthe thin-film encapsulation layer 300. In addition, the fifth test padTP11, the sixth test pad TP12, the seventh test pad TP21 and the eighthtest pad TP22 may not contact nor overlap the thin-film encapsulationlayer 300.

FIGS. 6 through 13 are cross-sectional views illustrating the process ofmanufacturing the portion of FIG. 4.

Referring to FIGS. 4 and 6 through 13, a buffer layer 111 is formed on abase layer 110 as illustrated in FIG. 6. Then, semiconductor layers 35and 135 are formed on the buffer layer 111. The semiconductor layers 35and 135 respectively include source portions 35 s and 135 s doped with ahigh concentration impurity, drain portions 35 d and 135 d, and channelportions 35 a and 135 a located between the source portions 35 s and 135s and the drain portions 35 d and 135 d.

Next, a gate insulating layer 113 is formed on the semiconductor layers35 and 135, and gate electrodes 25 and 125 are formed on the gateinsulating layer 113. In the process of forming the gate electrodes 25and 125, gate lines (not shown) are also formed.

Next, a first interlayer insulating film 115 is formed on the gateelectrodes 25 and 125.

Referring to FIG. 7, a first contact hole CH1 that exposes the sourceportion 135 s of the semiconductor layer 135, a second contact hole CH2that exposes the drain portion 135 d of the semiconductor layer 135, athird contact hole CH3 that exposes the source portion 35 s of thesemiconductor layer 35 and a fourth contact hole CH4 that exposes thedrain portion 35 d of the semiconductor layer 35 are formed in the firstinterlayer insulating film 115 and the gate insulating layer 113.

Referring to FIG. 8, a data metal layer 170 is deposited on the firstinterlayer insulating film 115 and patterned to form source electrodes73 and 173, drain electrodes 75 and 175, a data line 171, a power supplyline 71, and a first crack detection line CD1 including a first line CD1a and a second line CD1 b. The source electrode 173 is connected to thesemiconductor layer 135 via the first contact hole CH1, the drainelectrode 175 is connected to the semiconductor layer 135 via the secondcontact hole CH2, the source electrode 73 is connected to thesemiconductor layer 35 via the third contact hole CH3, and the drainelectrode 75 is connected to the semiconductor layer 35 via the fourthcontact hole CH4. As a result, a driving thin-film transistor Qd and acircuit thin-film transistor Ts are formed.

Although not illustrated in the drawings, if a second crack detectionline CD2 (see FIG. 1) is further provided, it may be formed in theprocess of forming the first crack detection line CD1.

Next, referring to FIG. 9, a first photoresist pattern PR1 and a secondphotoresist pattern PR2 are formed. The first photoresist pattern PR1 isformed on the first crack detection line CD1 and exposes side surfacesof the first line CD1 a and the second line CD1 b of the first crackdetection line CD1. The second photoresist pattern PR2 completely coversthe power supply line 71, the circuit thin-film transistor Ts, the dataline 171 and the driving thin-film transistor Qd. In particular, thesecond photoresist pattern PR2 covers the source electrodes 73 and 173,the drain electrodes 75 and 175, the data line 171 and the power supplyline 71, such that their side surfaces are not exposed.

Referring to FIG. 10, the side surfaces of the first line CD1 a and theside surfaces of the second line CD1 b are etched using the firstphotoresist pattern PR1 as a mask. Accordingly, each of the first lineCD1 a and the second line CD1 b has an inversely tapered cross-sectionalshape.

Next, the first photoresist pattern PR1 and the second photoresistpattern PR2 are removed to form a second interlayer insulating film 117and a first pattern 117 a as illustrated in FIG. 11. The secondinterlayer insulating film 117 may be formed on the driving thin-filmtransistor Qd and the circuit thin-film transistor Ts, and a fifthcontact hole CH5 exposing the drain electrode 175 of the drivingthin-film transistor Qd may be formed in the second interlayerinsulating film 117. The second interlayer insulating film 117 and thefirst pattern 117 a may be formed by coating a photosensitive organicmaterial on the first interlayer insulating film 115 and exposing anddeveloping the photosensitive organic material. The second interlayerinsulating film 117 and the first pattern 117 a may be separated fromeach other with the power supply line 71 interposed between them. Avalley V may be formed between the second interlayer insulating film 117and the first pattern 117 a to partially expose the power supply line71.

Next, a conductive material is deposited on the second interlayerinsulating film 117 and patterned to form a first electrode 210 and aconnection electrode 211. The first electrode 210 may be connected tothe drain electrode 175 via the fifth contact hole CH5, and theconnection electrode 211 may be connected to the power supply line 71via the valley V.

In some embodiments, the process of covering the first crack detectionline CD1 with a photoresist pattern may be performed before theconductive material is deposited.

Referring to FIG. 12, a pixel defining layer 220 and a second pattern220 a are formed. The pixel defining layer 220 may be formed on thesecond interlayer insulating film 117 and may include an opening OP thatexposes part of the first electrode 210. The second pattern 220 a may beformed on the first pattern 117 a to form a dam DM. In some embodiments,the pixel defining layer 220 and the second pattern 220 a may be formedby coating a photosensitive organic material and exposing and developingthe photosensitive organic material.

A light emitting layer 230 is formed on the first electrode 210 exposedthrough the opening OP, and a second electrode 250 is formed on thelight emitting layer 230 and the pixel defining layer 220. The secondelectrode 250 may be connected to the connection electrode 211 bypartially extending to the connection electrode 211 as described above.The first electrode 210, the light emitting layer 230 and the secondelectrode 250 may form an OLED LD, and the OLED LD and the pixeldefining layer 220 may form a display structure DS.

Referring to FIG. 13, a thin-film encapsulating layer 300 is formed toencapsulate the OLED LD or the display structure DS. In someembodiments, the thin-film encapsulation layer 300 may have a structurein which a first inorganic film 310, an organic film 330, and a secondinorganic film 350 are sequentially stacked on the second electrode 250.In the process of forming the thin-film encapsulation layer 300, a firstinorganic film pattern PT1 may be formed on the first line CD1 a, asecond inorganic film pattern PT2 may be formed on the second line CD1b, and a third inorganic film pattern PT3 may be formed between thefirst line CD1 a and the second line CD1 b. Since the first inorganicfilm pattern PT1, the second inorganic film pattern PT2 and the thirdinorganic film pattern PT3 are identical to those described above withreference to FIG. 4, they will not be described in detail.

Through the above process, the structure illustrated in FIG. 4 can bemanufactured.

FIGS. 14 through 18 are cross-sectional views illustrating the processof manufacturing the portion of FIG. 5.

Referring to FIGS. 5 and 14 through 18, a buffer layer 111, a gateinsulating layer 113, and a first interlayer insulating film 115 aresequentially formed on a base layer 110 in a pad area PA. The process offorming the buffer layer 111, the gate insulating layer 113 and thefirst interlayer insulating film 115 can be performed at substantiallythe same time as the process illustrated in FIG. 6.

Next, referring to FIG. 15, a data metal layer 170 is deposited on thefirst interlayer insulating film 115 and patterned to form a first testpad TP1, a second test pad TP2, a first crack detection pattern CDP1including a first pattern CDP1 a and a second pattern CDP1 b, and a dataline 171. The process of forming the first test pad TP1, the second testpad TP2, the first crack detection pattern CDP1 including the firstpattern CDP1 a and the second pattern CDP1 b, and the data line 171 maybe performed at substantially the same time as the process of formingthe source electrodes 73 and 173 (see FIG. 8), the drain electrodes 75and 175 (see FIG. 8), the first crack detection line CD1 (see FIG. 8)and the power supply line 71 (see FIG. 8). Although not illustrated inthe drawings, a fifth test pad TP11 (see FIG. 1) and a sixth test padTP12 may also be formed. In addition, although not illustrated in thedrawings, if a second crack detection pattern CDP2 (see FIG. 1) isfurther provided, it may be formed in the process of forming the firstcrack detection pattern CDP1.

Next, referring to FIG. 16, a third photoresist pattern PR3, a fourthphotoresist pattern PR4, and a fifth photoresist pattern PR5 are formed.The third photoresist pattern PR3 may be formed on the first test padTP1 and the second test pad TP2, and side surfaces of the first test padTP1 and the second test pad TP2 may be exposed without being covered bythe third photoresist pattern PR3. The fourth photoresist pattern PR4may be formed on the first crack detection pattern CDP1, and sidesurfaces of the first pattern CDP1 a and the second pattern CDP1 b maybe exposed without being covered by the fourth photoresist pattern PR4.The fifth photoresist pattern PR5 may be formed on the data line 171 inthe pad area PA to cover side surface of the data line 171.

The third photoresist pattern PR3, the fourth photoresist pattern PR4and the fifth photoresist pattern PR5 may be formed at the same time asthe first photoresist pattern PR1 (see FIG. 9) and the secondphotoresist pattern PR2 (see FIG. 9).

Referring to 17, the side surfaces of the first test pad TP1, the sidesurfaces of the second test pad TP2, the side surfaces of the firstpattern CDP1 a and the side surfaces of the second pattern CDP1 b areetched using the third photoresist pattern PR3 and the fourthphotoresist pattern PR4 as a mask. Accordingly, each of the first testpad TP1, the second test pad TP2, the first pattern CDP1 a, and thesecond pattern CDP1 b has an inversely tapered shape.

Next, the third photoresist pattern PR3, the fourth photoresist patternPR4, and fifth photoresist pattern PR5 are removed.

In some embodiments, in the process of forming the thin-filmencapsulation layer 300 described above with reference to FIG. 13, afirst inorganic film 310 and a second inorganic film 350 of a thin-filmencapsulation layer 300 may also be formed in the pad area PA asillustrated in FIG. 18, and an organic film 330 (see FIG. 13) of thethin-film encapsulation layer 300 may be blocked by a dam DM (see FIG.13).

Accordingly, a fourth inorganic film pattern PT4 may be formed on thefirst test pad TP1, a fifth inorganic film pattern PT5 may be formed onthe second test pad TP2, and a sixth inorganic film pattern PT6 may beformed between the first test pad TP1 and the second test pad TP2. Inaddition, a seventh inorganic film pattern PT7 may be formed on thefirst pattern CDP1 a, an eighth inorganic film pattern PT8 may be formedon the second. pattern CDP1 b, and a ninth inorganic film pattern PT9may be formed between the first pattern CDP1 a and the second patternCDP1 b. The inorganic film patterns PT4 through PT9 in the pad area PAmay be simultaneously formed in the process of forming the thin-filmencapsulation layer 300 (see. FIG. 13). The fourth through ninthinorganic film patterns PT4 through PT9 may respectively include lowerinorganic film patterns 310 d through 310 i made of the same material asthe first inorganic film 310 and upper inorganic film patterns 350 dthrough 350 i made of the same material as the second inorganic film350.

After the process of FIGS. 13 and 18, the process of removing the firstinorganic film 310, the second inorganic film 350, and the inorganicfilm patterns PT4 through PT9 located in the pad area PA may further beperformed. The result is the structure illustrated in FIG. 5. Theprocess of removing the first inorganic film 310, the second inorganicfilm 350 and the inorganic film patterns PT4 through PT9 may be achievedby forming a photoresist pattern to expose the pad area PA and cover thenon-display area NDA excluding the pad area PA and the display area DAand removing the first inorganic film 310, the second inorganic film 350and the inorganic film patterns PT4 through PT9 located in the pad areaPA by using the photoresist pattern as a mask.

FIG. 19 is a schematic perspective view of the structure of the displaydevice 1 of FIG. 1 in a case in which the display device 1 is bent. FIG.20 is a cross-sectional view taken along the line X-X′ of FIG. 19. FIG.21 is a cross-sectional view taken along the line Y-Y′ of FIG. 19.

Referring to FIGS. 1 and 19 through 21, the display device 1 accordingto the current embodiment may be at least partially curved or bent.

For example, of the non-display area NDA of the display device 1, anarea located on the left side of the display area DA in the drawings maybe bent at a predetermined curvature in a downward direction (or adirection opposite to a z-direction) of the display device 1 to form afirst bending area BA1. In addition, an area of the non-display area.NDA that is located on the right side of the display area DA in thedrawings may be bent at a predetermined curvature in the downwarddirection (or the direction opposite to the z-direction) of the displaydevice 1 to form a second bending area BA2. Also, the pad area PA (seeFIG. 1) of the non-display area NDA may be bent at a predeterminedcurvature in the downward direction of the display device 1 to form athird bending area BA3.

The first crack detection line CD1 (see FIG. 1) described above mayextend in the first bending area BA1 of the display device 1 along thefirst direction y to detect cracks in the first bending area BA1. Inaddition, the second crack detection line CD2 (see FIG. 1) describedabove may extend in the second bending area BA2 of the display device 1along the first direction y to detect cracks in the second bending areaBA2. The first crack detection pattern CDP1 (see FIG. 1) and the secondcrack detection pattern CDP2 (see FIG. 1) may detect cracks in the thirdbending area BA3.

FIG. 22 is a schematic perspective view of the structure of a modifiedembodiment of the display device 1 illustrated in FIG. 19. FIG. 23 is across-sectional view taken along the line Xa-Xa′ of FIG. 22. FIG. 24 isa cross-sectional view taken along the line Ya-Ya′ of FIG. 22.

Referring to FIGS. 22 through 24, a display device 1 a according to thecurrent embodiment may be substantially the same as the display device 1illustrated in FIGS. 19 through 21 except that part of a display area DAis included in each of a first bending area BA1 and a second bendingarea BA2.

The first crack detection line CD1 (see FIG. 1) may extend in anon-display area NDA of the first bending area BA1 of the display device1 a along the first direction y to detect cracks in the first bendingarea BA1. In addition, the second crack detection line CD2 (see FIG. 1)may extend in the non-display area NDA of the second bending area BA2 ofthe display device 1 a along the first direction y to detect cracks inthe second bending area BA2. The first crack detection pattern CDP1 (seeFIG. 1) and the second crack detection pattern CDP2 (see FIG. 1) maydetect cracks in the third bending area BA3.

In FIGS. 22 through 24, part of the display area DA is included in eachof the first bending area BA1 and the second bending area BA2. However,this is merely an example. That is, in some embodiments, part of thedisplay area DA may be included in the first bending area BA1 but maynot be included in the second bending area BA2.

FIG. 25 is a schematic perspective view of the structure of a modifiedembodiment of the display device 1 illustrated in FIG. 19. FIG. 26 is across-sectional view taken along the line Xb-Xb′ of FIG. 25. FIG. 27 isa cross-sectional view taken along the line Yb-Yb′ of FIG. 25.

FIGS. 25 through 27, a display device 1 b according to the currentembodiment may be substantially the same as the display device 1illustrated in FIGS. 19 through 21 except that part of a display area DAis included in each of a first bending area BA1, a second bending areaBA2 and a third bending area BA3.

Referring to FIGS. 25 through 27, part of the display area DA isincluded in each of the first bending area BA1, the second bending areaBA2 and the third bending area BA3. However, this is merely an example.That is, in some embodiments, part of the display area DA may beincluded in the third bending area BA3 but may not be included in thefirst bending area BA1 and the second bending area BA2. Alternatively,part of the display area DA may be included in the third bending areaBA3 and any one of the first bending area BA1 and the second bendingarea BA2.

The first crack detection line CD1 (see FIG. 1) may detect cracks in thefirst bending area BA1 of the display device 1 b, and the second crackdetection line CD2 (see FIG. 1) may detect cracks in the second bendingarea BA2 of the display device 1 b. In addition, the first crackdetection pattern CDP1 (see FIG. 1) and the second crack detectionpattern CDP2 (see FIG. 1) may detect cracks in the third bending areaBA3.

According to an embodiment, cracks in a display device can be easilydetected. Therefore, defects of the display device due to cracks can beprevented.

However, the effects of the inventive concept are not restricted to theone set forth herein. The above and other effects of the inventiveconcept will become more apparent to one of daily skill in the art towhich the inventive concept pertains by referencing the claims.

What is claimed is:
 1. A display device comprising: a display area and anon-display area located around the display area; a base layer; anorganic light-emitting diode (OLED) that is located on the base layer inthe display area; and a first crack detection line that is located onthe base layer in the non-display area; wherein the first crackdetection line comprises a first line that extends substantially in afirst direction along a first edge of the display area, a second linethat is separated from the first line and extends substantially in thefirst direction, and a third line that is connected to an end of thefirst line and an end of the second line, wherein a cross-sectionalshape of the entire first line in a second direction crossing the firstdirection is inversely tapered.